Improvement in blasting rogks under water



B. MAILLEFERT.

Torpedo. No, 8,776. Patented Mar. 2,1852.

N PETERS. PHOTO-LITHOGRAPHEIL WASHINGTON D O,

UNITED STATES 'ATENT FFICEQ IMPROVEMENT IN BLASTING ROGKS UNDER WATER.

Specification forming part of Letters Patent? No 8,776., dated March 2,1852.

To all whom it mayconce-rn Beit known that I, BENJAMIN MAILLEFERT, of New York, N. Y., have invented a certain .new and useful Method of Blasting Rocks Under Water without Drilling or Boring; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawing, male ing part of this specification, which drawing represents an elevation of the apparatus as applied to a rock under water preparatory to the blasting.

It has always heretofore been the practice in all attempts to blast rocks under water to insert the explosive charge in a cavity in or under the rock, under the impression that the rock could not be separated or removed unless the charge were confined within the mass of the rock, or in some suitable cavity under it, or between it and the solid bottom upon which it rests; and, as the drilling of a rock or the making of the required excavation under it for the reception and confinement of the charge is attended with great labor and difficulty when made under water, the discovery of some easier and cheaper method has been for along time a desideratum. I have discovered, however, that if the explosive charge be confined in a separate vessel and placed on the surface of the rock, and there held until discharged, the surrounding water presents a suflicientresistance to the expanding gases evolved by the explosion to eifeot the disintegration of the most tenacious rocks. As the resistance of water to the passage of bodies through is as the squares of the velocity and evolution of gases by the explosion is very rapid, I concluded that a resistance would thus be presented by the water which would be quite sufficient to efl'ect the purpose, avoiding thereby the expense and labor of preparing the rock for the insertion of the charge.

The mode of procedure which I have practiced with success is as follows: I take a canister, a, made of tin or or other substance, and fill it with gunpowder or its equivalent, and when charged close it'up so as to prevent access of water to the powder. The said canister is provided with one or'rnore loops or staples, b, adapted to slide on a guide-rod, d, which is let down onto the surface ofthe rock e from a boat, f, and after the said guide-rod has been let down in the water to the surface of the rock to be blasted the loop or staples b are slipped onto the said rod, and the canister is then let down by a cord, rope, or chain, g, from the boat f. To the said canister is attached a conducting-wire, h, from a suitable galvanic battery, 1', either on shore or in a boat, j, anchored or placedat a sufiicient distance not to be injured by the blast. The conductor h, it.will be understood, passes through the canister to the powder or other igniting and exploding substance therein. After the canister has been let down onto the rock the guide-rod d can be withdrawn and the boat moved away far enough not to be injured by the agitation of the waterconsequent upon the explosion, which is effected by the galvanic battery through the conductor h,- and as the battery and themannerof exploding gunpowder under water by means of electric currents is well known,it is deemed unnecessary to give a description of this partof the mode of procedure.

Care should be taken, by weights or other known means, so to place the canister or other vessel containing the charge that it will not be carried away by the tide or current before the explosion takes place. The part of the surface of the rockto which it is to be applied must depend upon the form of the rock and the part to be removed, and therefore it can be applied either to the top or the side, as in either case the surrounding water will present the required resistance .to efl'ect the disintegration of the rock.

The canister can be made of any desired form, and of any suitable material which can be scaled up to keep out the water and which will readily yield to the explosion; and the quantity of gunpowder for each charge will of course depend on the size of the rock and the quantity to be removed. In the experiments made by me in the harbor of New York such charge consisted of one hundred and -gunpowder placed on or against such wrecks;

but I am not aware that it was ever before known that a solid mass, such as a rock, could be disintegrated by the explosion of gunpowder placed under water and on the outside of such mass. 1 do not therefore claim, broadly, the breaking up of hollow bodies under water bythe explosion of charges placed on the outside of such bodies. What I claim as my invention or discovery 1s- The blasting of rocks under water by placing the explosive charge or charges on or against the surface of the rock to be blasted and using the surrounding water as the means of resistance to the explosion, substantially as herein specified.

BIN. MAILLEFER-T.

Witnesses CAUSTEN BROWNE, JAMES SHIELDS. 

